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So, there is an issue with that wallet for sure. Keep rolling for almost 15 minutes and nothing is happening. Just tried with esteem and nothing happen as well. Can't delegate or power down.

That might be some issue with your workstation / connection, that for some reason can't connect to Steem API nodes (just guessing now), could you check if going to https://api.steemit.com/ gives you response like:

{"status":"OK","datetime":"2019-12-20T09:14:41.772867","source_commit":"ae6c6c77601436e496a8816ece2cbc6e26fbe3c2","docker_tag":"latest","jussi_num":39198399}

?

Here is what that gives :

{"status":"OK","datetime":"2019-12-21T08:09:42.125620","source_commit":"ae6c6c77601436e496a8816ece2cbc6e26fbe3c2","docker_tag":"latest","jussi_num":39225853}

I still think that I need more power to reveal my active key. I can send more steem to this account and power up, but I'm not sure about the reason why this is happening. I'm afraid that something wrong is with the account and no matter how much steem power i will have here, it will be stock forever.

Please tell me what to do.

Server response seems OK, so it's hard for me to guess what's the reason that you can't use Vessel.
No, Steem Power is irrelevant when it comes to keys.
Can you come to Steem.Chat to discuss that issue?
Either #help channel and/or contact me directly on chat

(Never ever give your password or key to anyone!)